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5200 bottom ???

Uh? He said it so it must be true? Or saying it to give people what they want to hear / read?
Thing is, I've been wondering where people who love wooden boats on the other site but, really don't know about Wooden Boats were getting their information / misinformation.

Re: 5200 bottom ???

No question.. I'd never do it don't care how "great" it is. my opinion. I know many others may have and can offer their own perspective. I was not referring to cold molded or epoxy. and this is about double plank & seams with 5200. I don't think I misread the website where he goes at length to describe. I will go back and read more see if it will change my opinion.

Quote;"then use new mahogany planking supported by marine grade plywood as the inner layer sealed in a proper and flexible wood sealer. The new lumber is attached with silicon bronze fasteners and 3M 5200 adhesive in lieu of the lead soaked canvas between the inner and outer layer. The 5200 product comes in a caulk tube which is applied to the inner layer (marine grade plywood) before attaching the outer mahogany planking. "

The writer also mentions the plywood is epoxy coated. prior to 5200 being trowled on (like tile adhesive)

I own a 23' 1952 Chris-Craft that has a 5200 bottom done 15 years ago and it is sound and bone dry.
This process is no different than the original construction. In lieu of using the canvas bedding material, between bottom planks 3M5200 is used as a permanent membrane. Bottom no longer needs to swell. Screws are replaced with stronger silicone bronze that no longer break due to swelling and drying of the boat bottom.

I am restoring a barn find '52 18' Chris-Craft Riviera and am following Don's book. The boat was falling apart just as Danenberg documents. 1 in 5 screws were broken and frames split just like the pictures in the book.

Most top Chris-Craft restoration services will install an original bottom for the purists, but they will gladly do a 5200 bottom. A lesser number will use a West epoxy bottom (no fiberglass) however they have just as much experience as Don and it works just fine. I know this because I have visited these shops and the Classic Boat community regularly discusses this topic.

One oddity though - the new wood runabouts/utilities now built by Hacker-Craft, Gar-wood, Grand Craft, Van Dam etc use cold molded construction, but were designed for this. These boats cost $125k - Over a $1m

I own a 23' 1952 Chris-Craft that has a 5200 bottom done 15 years ago and it is sound and bone dry.
This process is no different than the original construction. In lieu of using the canvas bedding material, between bottom planks 3M5200 is used as a permanent membrane. Bottom no longer needs to swell. Screws are replaced with stronger silicone bronze that no longer break due to swelling and drying of the boat bottom.

I am restoring a barn find '52 18' Chris-Craft Riviera and am following Don's book. The boat was falling apart just as Danenberg documents. 1 in 5 screws were broken and frames split just like the pictures in the book.

Most top Chris-Craft restoration services will install an original bottom for the purists, but they will gladly do a 5200 bottom. A lesser number will use a West epoxy bottom (no fiberglass) however they have just as much experience as Don and it works just fine. I know this because I have visited these shops and the Classic Boat community regularly discusses this topic.

One oddity though - the new wood runabouts/utilities now built by Hacker-Craft, Gar-wood, Grand Craft, Van Dam etc use cold molded construction, but were designed for this. These boats cost $125k - Over a $1m

In closing, I guess my question, if I were to ask one would be:

Where are people getting the idea that 5200 is an alternative for caulking Carvel plank boats???

Clearly, as in most things people only take what they want to know or read out of a book, website or other source of information, this must be, at least partially, what is driving the idea of 5200 as "caulking"

Re: 5200 bottom ???

"Where are people getting the idea that 5200 is an alternative for caulking Carvel plank boats???" Experience. Danenberg starting using 5200 in the early 80's and has an excellent reputation (did you read his bio?). These boats are a modification of carvel planking - it is batten seam carvel. No caulking required. Side boards are butted tight. Bottom boards are gapped 1/16" on a double planked bottom and bedded in 5200.

These old runabouts used bedding compounds in construction. Think of the 5200 as a bedding compound and perhaps the riddle is solved.

Quote by Tom Freston - Innovation is taking two things that already exist and putting them together in a new way

Re: 5200 bottom ???

DeniseO30 is correct in understanding that in carvel construction caulking is most important - really essential to the structure.

There are double planked hulls, both parallel planked with staggered seams and cross planked, where the individual planks are narrow enough that the planks can be placed almost as tightly fitted as tight seam planking so that when swelled the hull has correct skin compression. Even where a gap is left, they can be gooped in the seams because there's the structure and waterproofing of the double planking. In old times, between the layers was often further protected by a layer of canvass heavily dosed with white lead. Now 5200 and other products can be troweled on to the same effect.

Might add that 5200, SikaFlex, and similar products are also used as a seam compound atop caulking on carvel boats. I know of one old yawl that had her garboard seam reefed out and the owner squirted in SikaFlex with no caulking. As predicted by everyone, that opened right up the moment sail was raised. On the other hand, an ancient cabin cruiser that was really serving as a home, had no engines in her, and was never even towed more that 200' for an annual shave&haircut, had her caulkless seams glooped over with 5200 and for that use was fine for her last decade or so.

Re: 5200 bottom ???

Originally Posted by wizbang 13

CC boats are not carvel . Their board n batten on the sides and double planked on the bottom.

Yes, for the most part. Just to be perfectly accurate - some earlier Chris Craft boats were built in a traditional carvel-planked, plank-on-frame fashion. But those are quite rare, and not at all what people think of when they talk about CC boats. Or 'mahogany runabouts'.

And, yes, the Danenburg 5200 method is well-proven, and seems to hold up well. I've watched it be done, and have done some minor repairs and/or refinishing on boats that have been restored that way. I'd have no problem recommending it.

David G
Harbor Woodworkshttps://www.facebook.com/HarborWoodworks/

"It was a Sunday morning and Goddard gave thanks that there were still places where one could worship in temples not made by human hands." -- L. F. Herreshoff (The Compleat Cruiser)

Re: 5200 bottom ???

I'm sorry the title is not quite what I should of been here.

There are just so very many people "out there" that are in the "just wanna get it launched" mentality and they keep buying old boats and a few months later come back trying to find out "what it's worth, I can't afford to restore it" mentality.

I know you all love CCs but it really wasn't about them. Just the 5200 method gave me a double take. I'm down with it now and understand.

Re: 5200 bottom ???

Wow, I've bitten my tongue more than once when seeing 5200 being used for some applications. All I can say is most "experts" and users aren't around 15-20 yrs later to see what their 5200 use actually did. Its fine to get a boat project out the door and have a few good years of a tenacious flexible bond but...5200 gets hard as a rock over time, hard like a bowling ball. It also stress cracks (evidenced by early sailboat production hull to deck joints that now leak due to 5200 cracking failure). I still have two glass boats that I used 5200 on in the mid 1980s. By the time the late 1990s came I found those issues. I will say it never lost it tenacity though.

Re: 5200 bottom ???

I laid Boatlife (polysulfide?) between 2 layers of aluminum while reinforcing the bottom of my 14' aluminum boat back in the mid 90s. I added 1/8" to the thickness, it was oil canning in rough water. More than 20 years later the squeeze out is still just as tough and flexible as it was then. It may be a better product for the described use.

Re: 5200 bottom ???

Originally Posted by Gib Etheridge

I laid Boatlife (polysulfide?) between 2 layers of aluminum while reinforcing the bottom of my 14' aluminum boat back in the mid 90s. I added 1/8" to the thickness, it was oil canning in rough water. More than 20 years later the squeeze out is still just as tough and flexible as it was then. It may be a better product for the described use.

While I should know better than to weigh in on this, I was thinking along the lines of something better than 5200 for the purpose. I was thinking along the lines of a liquid PU made for roller application that sdowney717 liked such as sanitread or a lagging compound like CP-50A HV2 or one of the liquid EPDM roofing materials. Polysulfide might be the best choice.

The links provided in post #5 describe three alternatives for replacing the bottom of a CC boat. One is the original 6 year life bottom, one is a hybrid Ascroft/West that uses some plywood to support a mass of microfiber filled West epoxy (inaccurate description) and the last is a brief description of a similar process except instead of epoxy, bedding planks in 5200. I would tend to favor the original WEST System where the longitudinal strip planks covered with diagonal strips.

Originally Posted by wizbang 13

Where is the carvel boat on this thread?
Who is saying devil sperm(5200) is an alternative for cotton?

Originally Posted by DeniseO30

Wiz, in my very first post I mentioned the other site (Facebook)

It was unclear where the caulking argument originated. You gave no indication that somewhere in the vast morass that is facebook one might stumble upon the use of devil sperm for caulking carvel planks. How should anyone know that the other thread was on faceplant? Well, that was harsh.

Management is the art of counting beans. Leadership is the art of making every being count. --Joe Finch

Re: 5200 bottom ???

Originally Posted by DeniseO30

In closing, I guess my question, if I were to ask one would be:

Where are people getting the idea that 5200 is an alternative for caulking Carvel plank boats???

Clearly, as in most things people only take what they want to know or read out of a book, website or other source of information, this must be, at least partially, what is driving the idea of 5200 as "caulking"

Sent from my LG-M430 using Tapatalk

We should back up a tad. First, a CC runabout, or any runabout with a plywood inner skin and plank on the outside is not a carvel planked boat. Second, CC never used caulking on their boats with double planking. They were tight fit. Third, a 5200 bottom is not using 5200 as caulking.

Other than that, your comments are fine. You are entitled to question 5200 bottoms on restorations like this. I doubt Don Dannenberg and all the other high end classic boat restorers give a crap. Oh, just for a final comment SDowney doesn't have much of an idea of what he's doing in my opinion, but of course, that is just my opinion, based on my experience. YMMV. No, I don't post much here anymore. Why bother, when this is the kind of thread I would be replying to.

Wow, I've bitten my tongue more than once when seeing 5200 being used for some applications. All I can say is most "experts" and users aren't around 15-20 yrs later to see what their 5200 use actually did. Its fine to get a boat project out the door and have a few good years of a tenacious flexible bond but...5200 gets hard as a rock over time, hard like a bowling ball. It also stress cracks (evidenced by early sailboat production hull to deck joints that now leak do to 5200 cracking failure). I still have two glass boats that I used 5200 on in the mid 1980s. By the time the late 1990s came I found those issues. I will say it never lost it tenacity though.

Bill, you are right and it's why It was kind of like a double-take for me, because 5200 gets like Stone after so many years.

Gentleman it doesn't have to be an argument and I wasn't referring to one or trying to start one, it's just sometimes, I get surprised by the things I see and then the things I look up and find out.

I don't even try to track or follow most of the input on the Facebook group it's almost impossible to track, going back over activity logs scrolling down doing a search so very tedious.

Re: 5200 bottom ???

Lotta flotsom and jetsom on the Facebook page.
I believe it's not actually part of this here. I have been frustrated there, trying to answer questions of nubes.
Nice place for pretty pictures,and nothin wrong with that.
bruce

Re: 5200 bottom ???

Originally Posted by Peter Malcolm Jardine

We should back up a tad. First, a CC runabout, or any runabout with a plywood inner skin and plank on the outside is not a carvel planked boat. Second, CC never used caulking on their boats with double planking. They were tight fit. Third, a 5200 bottom is not using 5200 as caulking.

Other than that, your comments are fine. You are entitled to question 5200 bottoms on restorations like this. I doubt Don Dannenberg and all the other high end classic boat restorers give a crap. Oh, just for a final comment SDowney doesn't have much of an idea of what he's doing in my opinion, but of course, that is just my opinion, based on my experience. YMMV. No, I don't post much here anymore. Why bother, when this is the kind of thread I would be replying to.

SDowney has been willing to experiment with a number of products that most of us are too conservative to consider. He has had some success and deserves some credit for not only trying something new but posting the results. AFAIK he will admit when something doesn't work out. This forum can be a bit of a crab bucket when someone strays too far, and he is a prime example of the crab that tries to climb out. His Sanitred Permaflex could be a 'replacement' for Cascover. He had some adhesion issues on his keel, but that may have some issues with the condition of the wood before coating. If you wetted and stretched SOF type ballistic nylon over a hull and coated with Permaflex or Spirit Line PU, the surface might not be as hard as Cascover, but it would certainly be durable. Yes, there are issues with covering rotten hulls (DONT).

I don't share his enthusiasm for PL Premium, and I have serious reservations about 3M 5200 based on the comments about it hardening over time. Chris Craft used tarred canvass, which seems to last roughly 6 years according to the websites linked in post #5.

This is the process we are discussing: https://www.youtube.com/watch?v=luEaJZvl77U One ACBS video said it would take 40 tubes to do a boat, which comes to 3 gallons. Excellent hand grip exercise, but I would prefer bulk for that much material.

5200 in a tube has its drawbacks, including cost and long term durability. (3 gal., $215 from Jamestown)
Polysulfide is softer, and should be very stable http://www.skygeek.com/flamemaster-c...ant-black.html (3 gal., $165 from Skygeek)
Sanitred is stronger and should have excellent environmental resistance. One of the harder materials, 80 Shore A, see the tds below.